diff --git a/services/gmail.js b/services/gmail.js
index d1d5662..f22dacd 100644
--- a/services/gmail.js
+++ b/services/gmail.js
@@ -305,7 +305,7 @@ async function sendGmailReply(
        </table>
     </div>`;
 
-  const boundary = `\000000000000${Date.now().toString(16)}`;
+  const boundary = '000000000000' + Date.now().toString(16);
 
   const plainBody = [];
    plainBody.push(replyText);